When You Fast is a guided fasting program built on a simple idea: fasting is hard to start and harder to finish alone. Lenox Systems built the client the whole thing — the public program site, the paid enrollment flow, and a full operations CRM that runs every email a faster receives from the day they sign up to the reflection they leave at the end.
The problem
A guided fast is a content product with a clock attached. Someone starting the 21-Day Daniel Fast on a Tuesday needs a different email on day four than someone who started three weeks earlier, and both need it at the right hour of their own morning. Do that for five programs of different lengths, and the scheduling problem stops being something you can run out of a mailbox and a spreadsheet.
The client had the programs, the writing, and the theology. What they didn’t have was the machinery: a way to take payment, enroll someone into the right sequence, send the right message on the right day, and know afterwards whether any of it landed.
The hard requirement wasn’t the sending. It was the ownership — the client needed to change program content and email copy themselves, without a developer in the loop and without touching code.
What we built
Two surfaces on one system: a public site where people choose a fast and pay for it, and an operator portal where the client runs the program.
Template builder Rules · Variables
Named, reusable email templates with default subject and inbox preview text. Upload an HTML file or paste markup, and a live preview renders it immediately — with a light/dark toggle, because a fasting email lands at dawn on a phone in either mode. Merge variables insert with a click, and rules decide which template a given faster gets.
Guidance drip Per program
Each of the five fasts carries its own day-by-day sequence — welcome email, daily content, and a post-fast survey — scheduled relative to the faster’s own start date rather than a shared calendar.
Broadcasts Scheduled
One-off sends to a chosen segment, composed from a template and scheduled ahead. Every broadcast carries a lifecycle — draft, scheduled, sent, canceled — so a message queued for tomorrow morning can still be pulled back tonight.
Audience Resend sync
Contacts, segments, topics and custom properties, kept in sync with Resend in both directions. Each contact carries their current fast, completion count, spend, and subscription state, so a segment can be built from where someone actually is in the program.
Delivery telemetry Webhooks
Resend webhooks feed eight event types back into the portal — sent, delivered, opened, clicked, bounced, complained, suppressed, delivery delayed — which is what makes per-email open rates real numbers instead of guesses.
Operator dashboard Stripe · Resend
A single view over enrollment and delivery: active and completed fasts, revenue, a landing→checkout→paid→onboarded→opened funnel, completion rate by program, and open rates broken out by position in the sequence — so a weak day-three email is visible as a weak day-three email.
Measuring something harder than clicks
Most email dashboards stop at opens. This one carries a spiritual impact score alongside them, gathered from post-fast reflections that fasters explicitly consent to share. It sits next to revenue and open rate in the same view, which is a deliberate statement about what the program is actually optimising for.
The stack
The result
When You Fast is live at whenyoufast.com with five programs running, from a one-day fast to the full forty. The client writes and schedules every email themselves through the template builder — new copy, new sequences, and new broadcasts ship without a deploy and without us.
That was the point. The interesting engineering here isn’t the sending; it’s that the person who wrote the program is the person who operates it.